The invention relates to a method for synchronization of assemblies in a base station with a reference clock signal.
It is known for a so called “master oscillator” that must have a high absolute frequency accuracy to be used to synchronize remote units or assemblies in a base station. In this case, the oscillator is tuned via a phase-locking loop to a reference signal of a generally external reference source.
For example, a GPS (“Global Positioning System”) signal that is received via a GPS antenna is used as reference for an absolute time accuracy or phase accuracy. The GPS antenna is usually arranged in this case near a transceiving antenna in the base station. The received GPS signal must then usually be led to the master oscillator via a relatively long path by using a transmission link or line specifically provided therefor. This generally takes place together with a substantial signal damping owing to the line length. In addition, high costs are caused by the line length and by an additional outlay on line installation costs.
These disadvantages are significant, particularly in the case of spatially separated assemblies in a base station that is designed as a tower mounted radio arrangement. In this case, a first assembly, denoted as a radio head, is arranged close to the antenna, while further assemblies are arranged remote from the antenna. It is correspondingly necessary for both the remote first assembly and the remaining assemblies to be synchronized in time with the reference signal in a highly precise fashion.